Purged air hydraulic fluid system

ABSTRACT

A HYDRAULIC SYSTEM EFFECTIVE TO REMOVE AIR FROM HYDRAULIC FLUID AT THE INTAKE SIDE OF A PUMP AND AN AIRLIQUID SEPARATING STRUCTURE INCORPORATING AN ACCELERATION SLEEVE, A VARIABLE ORIFICE AND A DISPERSER SLEEVE EFFECTIVE TO DRAW SAID AIR FROM SAID INTAKE SIDE FOR DISPERSAL WITHIN A RESERVOIR.

Jan. 5, 1971 W J, KUDLA'TY 3,552,874

PURGED AIR HYDRAULIC FLUID SYSTEM Filed Feb. 1o. 1965 'United StatesPatent O F U.S. Cl. 415-121 11 Claims ABSTRACT OF THE DISCLOSURE Ahydraulic system effective to remove air from hydraulic fluid at theintake side of a pump and an airliquid separating structureincorporating an acceleration sleeve, a variable orifice and a dispersersleeve effective to draw said air from said intake side for dispersalwithin areservoir.

SUMMARY OF THE INVENTION A hydraulic system having a pump and return orrelief valve discharge conduit and incorporating means for separatingair from hydraulic fluid on the suction or intake side of the pump, saidmeans including an acceleration-diffuser sleeve operable in response tothe flow of said fluid in the return or relief valve discharge conduitto create la lowered pressure effective to produce such separation. Theinvention includes a variable orice in association with the accelerationsleeve and a disperser sleeve formed and adapted to disperse the air andhydraulic fluid downstream of the acceleration sleeve and within areservoir, a bypass or relief valve structure being associated with thedisperser sleeve to protect against back pressure.

This invention relates to hydraulic systems and has particular relationto a system and structure effective to remove air from the hydraulicfluid at the intake side of a pump in the system.

When air, whether dissolved, entrained or otherwise associated with thehydraulic fluid, enters a hydraulic pump, it is compressed and heated,causing sludging, facilitating corrosion, decreasing efficiency andreducing the life of the fluid and the pump. Hence it is one purpose ofthe invention to provide a hydraulic system and structure effective tosubstantially eliminate the delivery of air to the intake side of ahydraulic pump.

Another purpose is to facilitate the separation of air from hydraulicfluid at the return or pressure relief valve discharge conduit and thusto increase the density and bulk modulus of the fluid.

Another purpose is to provide an air-purging means which shall beindependent of pump output volume and effective with variable volumepumps.

Another purpose is to provide a hydraulic system having an air-liquidseparating structure effective in the high velocity and lower oratmospheric pressure segment of the system.

Another purpose is to provide an air-liquid separating structure capableof creating a liquid velocity in the range of 100 feet per second andabove and capable of employing said velocity in a venturi zone effectiveto evacuate air from the intake side of a pump.

V'Another purpose is to provide a completely automatic air-liquidseparating system operable in response to liquid flow therein andrequiring no manual attention or maintenance.

Another purpose is to provide an air-liquid separating structure capableof ready incorporation in existing systems and requiring minimalmodification in said systems.

Another purpose is to provide an air-liquid separating structureproductive of minimum back pressure and usable Patented Jan. 5, 1971 ICCwith a wide range of liquid viscosities and line flow pressures.

Another purpose is to provide an air-liquid separating structureincluding an evacuation conduit, a body element having a high velocityventuri section and an outlet baflle and a disperser sleeve andsecondary baffle, the elements thereof being independently replaceablewith minimum disturbance of the system or elements.

Another purpose is to provide an air-liquid separating structureoperable in variable positions and incorporating variable mesh sizescreens.

Another purpose is to provide a hydraulic system incorporating anair-liquid separating structure having elements immersed in a liquidreservoir.

Another purpose is to provide an air-liquid separating structure ofminimum size, weight and cost, having a minimum number of moving parts,of maximum ease of installation and removal and of maximum efficiencyand simplicity in operation.

Other purposes may appear from time to time during the course of thespecication and claims.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated more orless diagrammatically in the accompanying drawings wherein:

FIG. l is a schematic view of the system of the invention;

FIG. 2 is an enlarged scale side elevation in partial cross section,illustrating an air-liquid separating structure of the invention;

FIG. 3 is a side view in partial cross section and illustrating avariable form;

FIG. 4 is an illustration, on a reduced scale, of the device of FIG. 2in one vertical position; and

FIG. 5 is a view similar to that of FIG. 4 and illustrating the deviceof FIG. 2 in a second vertical position.

Like parts are indicated by like numerals throughout the specificationand drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,and particularly to FIG. l, the numeral 1 generally designates ahydraulic pump. An intake conduit 2 has a filter structure 3 therein. Areturn or relief valve discharge conduit 4 delivers hydraulic fluid to alower portion of a hydraulic fluid reservoir 5.

Positioned beneath the minimum working level of hydraulic fluid inreservoir 5, and thus immersed in said fluid, is an air-liquidseparating structure indicated generally by the numeral 6. It will beobserved that the structure `6 is connected to the delivery end ofconduit 4. An outlet for reservoir 5 is indicated at 7. An airevacuation conduit i8 is connected at one of its ends to structure 6 andat its opposite end to an upper portion of lllter 3.

It will be realized that various elements may, in accordance with knownpractice, be incorporated in the hydraulic system of FIG. l. The machineor element requiring hydraulic fluid, appropriate valves, filters andthe like, may, for example, be incorporated at suitable locations in thesystem. In the interest of clarity and has an axial, forwardlyconverging, conical through-bore 11 in which is positioned a forwardlyconverging, frustoconical hollow acceleration sleeve 12. The sleeve 12has a rearward, annular flange portion 13 seated against acorrespondingly shaped land a of the body 10 and is suitably heldthereagainst by the forward edge of conduit 4. It will be observed thatthe external diameter of the conical portion of sleeve 12 is less thanthe inner diameter of the -bore 11, thus creating a conical,circumferential evacuation chamber 14. A laterally disposed passage 15is formed in the body 10 and communicates at its inner end withevacuation chamber 14. The outer end of passage 15 is suitably threadedor formed to receive one end of evacuation or air suction conduit 8.

The forward end face of sleeve 12 is outwardly flared or chamferedcircumferentially from its inner to its outer edge, as indicated at A17.The outwardly flared surface 17 terminates at the forward mouth of thecircumferential evacuation chamber 14 and the surfaces of sleeve 12presented to liquid flowing therethrough are thus the frusto-conicalsurface 16 and ilared end surface 17.

A bar or strap 20 extends across the forward open end of a `ring 21encompassing the area about the mouths of sleeve 12 and chamber 14 andserving as a baille against which liquid and air impinges before passingon opposite sides of bar 20` Ring baille 21 is secured to body 10 byfasteners 21a extending through the wall of ring 20 and securing member20. A flow disperser, variable orificeforming member 22 has a conicalseat 23 formed and adapted for seating against the surface 17. Spring 24may engage opposed surfaces of members 20 and 22 to urge the surface 23toward the surface 17. The member 22 has an axial extension 25 slidablyreceived in a central opening 26 in the member 20.

Removably secured to the body 10 and extending forwardly therefrom is a`disperser sleeve 30. The sleeve 30 may be suitably secured to the body10 as, for example, by a wire coil member 31 having its opposite endsreceived in suitable pockets 32, 33 formed in the external surface ofthe body 10.

The sleeve 30 constitutes a circumferential tubular member having a wall34 formed appropriately of perforated metal and arranged coaxially withsleeve 12 and member 22, the rearward portion of wall 34 encompassingthe outlet of sleeve 12 and chamber 14 and extending forwardlytherefrom. As illustrated in FIGS. 1 and 2, the disperser sleeve 30 hasits lower half covered with a screen formed of line mesh filteringmaterial, such as a wire screen 35 for example. The forward end ofsleeve 30 carries an end cap or baille 36 having a central aperture 37normally closed by a relief valve plate 3-8 held in the position shownby a suitable spring 39 engaging an axial rod 40 secured to the plate 38and extending through a central aperture in a strap 40a across aperture37.

Referring now to FIG. 3, a body member 100 is suitably secured toconduit 4. Formed in the body 100 is a forwardly converging conical bore111 in which an acceleration sleeve 112 is positioned. The outerdiameter of sleeve 112 and inner diameter of bore 111 are such as tocreate the circumferential space or evacuation chamber 114 with whichthe laterally disposed passage 115, formed in the body 100 communicates.A retainer 113 is suitably supported by fasteners 121 and a spring 124engages the retainer 113 and a llow disperser member 122.

Member 122 takes the form of a cup-shaped element having its inner basewall 122a presented to the mouth of sleeve 112 and chamber 114. Afrusto-conical central portion 122b of base wall 122a rises therefrom topresent its domed upper end portion 122C and within the mouth of sleeve112. It will be observed that sleeve 112 and member 122 are convenientlyand economically formed of relatively thin material and that theinterpretation thereof provides suilicient seating, as at 112a, 122d, toclose the mouth of sleeve 112 when the parts are in the position shown.The bore 111 in body 100 continues in a reverse-cone counterbore portion111a paralleling, in spaced relationship, the conical surface of rise122b. The circumferential wall 122e of member 122 is flared outwardlyfrom base wall 122:1 and extends rearwardly in the same direction asrise 122b to encompass a forward portion of body within which the mouthof chamber 114 is located. The members 20 and 113 serve las stop meanslimiting the maximum size of the variable orifice created by members 22,122 as they move away from their respective seats 17, 112a.

The use and operation of the invention are as follows:

'In the system of FIG. l the evacuation or air separating conduit orline 8 communicates with the intake side of pump 1, preferably with anupper segment of a iilter housing normally present at said intake side.As liquid flows toward reservoir 5 in the system it` creates a venturior subatmospheric pressure zone in member 6 with which line 8communicates said intake side of pump 1. The pressure differential thuscreated separates and withdraws air from the liquid just prior to itsentry into pump 1 to preclude the compression and consequent heating ofthe air in the pump and thus to preclude and substantially reducesludging, corrosion and limitation of etliciency and life of the liquidand pump due to ingress of air thereinto.

The means for creating the pressure differential referred to aboveoperates automatically without human attention or maintenance and inresponse to the flow of liquid or hydraulic iluid in line 4 to member 6.Said flow accelerates in sleeve 12 or 112. With a normal flow in conduit4 of the order of 15 ft./sec., for example, the flow will accelerate toa speed of the order of 60 ft./sec. in sleeve 12, V112. In response tosaid flow, valve or disperser member 22, 122 will open, the springs 24,124 being of predetermined, normally relatively light forces. In anupwardly directed vertical position the spring may be discarded andgravity may be relied upon to close member 22, for example. In any casethe forces affecting the operation of member 22, 122 are known andpreset to provide for operation of the device at desired, normallyrelatively low, allow line forces. In the example cited, the liquidaccelerates from an order of 60 ft./sec. in sleeve 12, 112 to a speed inthe order of 100 ft./sec. or more as it flows through the variableorifice created by opposed seating faces 17, 23 of members 12, 22 or asat 112a, 122d of members 112, 122, to produce a venturi orsubatmospheric pressure zone at the mouth of and within chamber 14, 114,as well as within conduit 8. Thus air is drawn through conduit 8 fromthe intake of pump 1 to the area outwardly of and beyond the mouth ofchamber 14, 114.

The liquid ilows past the mouth of chamber 14, 114 at a velocity of 100ft. per second to overcome air-liquid cohesive forces and is dispersedby members 22, 122 into disperser sleeve 30. Air drawn from chamber 14,114 and in the liquid ilowing at high velocity thereacross, due to theirdiffering densities, will be propelled at different velocities and willtend to separate as the liquid ilows in an outwardly expanding patternmember 22 or along and from the rearwardly disposed edge of wall 122e ofmember 122. Thereafter, the disperser sleeve 30 provides a dispersal andseparation of said air, the hydraulic fluid or liquid flowing primarilythrough screen 35 and air through the relatively large perforations insleeve '30. Facilitating separation of air and liquid by means ofvelocities and through sleeve 30 and screen 35 serves to increase thedensity and bulk modulus of the uid. While the structure of theinvention is operative at velocities lower than those listed herein, itseffectiveness is increased at the velocities specified and higher.

When sleeve 30 is positioned horizontally, as in FIGS. 1 and 2, theI.bottom portion of its circumference is conveniently covered with apartial screen 35. When the structure is positioned vertically, acircumferential screen 35 is arranged about the lower portion of sleeve30 to provide for ready rise of air into the upper area of reservoir Sdevoid of liquid for appropriate discharge to atmosphere. Suitableconnections (not shown) may be provided for alternate or slidingrelationship of sleeve 30 and screen 35 to permit utilizing of the samestructure in either ofthe positions of FIGS. 4 and 5. The member 6,comprising elements -40, or with the elements of FIG. 3 substituted forcorresponding elements of FIG. 2, is positioned beneath the surface orworking level of lluid in reservoir 5, thus precluding malfunction inthe event of conduit leakage or slightly loose connections.

Should system contaminants seriously clog the openings in dispersersleeve 30 and screen 35, the relatively low pressure relief valvestructure 36-40a will open to preclude excessive system back pressureand consequent malfunction of valves (not shown) in the system.

Sleeve 30 and screen 35, with secondary baiiie and relief valvestructure 3640s, constitute a barrier member which is easily removedfrom and installed on a body such as body 10 Without disturbance to thetbody, to conduit 8 or to sleeve 12 or member 22 and associatedelements. Similarly, conduit 8 can be installed and removed from body10, 100 without disturbance of such a sleeve or any of the otherelements of FIG. 2. Member(6 can be varied in position with a merechange in location of mesh screen 35 which may be accomplished with easeand without disturbing any other elements.

While the system and structure is disclosed herein in relation tohydraulic fluid and finds a major application thereto, it will berealized that the same may be applicable to the separation of air orgases from other liquids without departing from the nature and scope ofthe invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are dened as follows:

1. 'For use in a hydraulic uid pressure system having a pump, an intakeelement for said pump, a hydraulic iiuid reservoir and a conduitdelivering hydraulic fluid to said reservoir, means for separating airfrom said uid at said intake element, including a iiuidflow-accelerating device in said reservoir and connected to saiddelivering conduit for reception of iiuid therefrom, an evacuationconduit communicating said intake element with said accelerating device,a disperser device secured to said accelerating device and positioned toreceive iiuid therefrom, said dispersed device including a barrierhaving openings of varying dimensions at upper and lower positionsthereof for passage of air through some of said openings and of iluidthrough others of said openings.

2. The structure of claim 1 characterized by and including animperforate baliie at the downstream end of said barrier and a reliefvalve carried by said baffle and formed and adapted to open a passagethrough said baiiie in response to uid pressure at said barrier beyond apredetermined level.

3. A liquid-ow-accelerating, subatmospheric pressure zone producingdevice responsive to the flow of liquid therethrough, said devicecomprising a body, a frustoconical, inwardly converging bore in saidbody, a frustoconical, inwardly converging sleeve in said Ibore andhaving a portion spaced from said bore to deline an evacuation chamberabout the smaller end of said sleeve, a frusto-conical,orifice-creating, liquid dispersing member having its smaller endportion yielding urged into a position closing said smaller sleeve endand movable therefrom in response to the iiow of liquid through saidsleeve to define an outwardly diverging conical oriiice in communicationwith said chamber and elective to accelerate the :llow of uid across anend portion of said chamber.

4. The structure of claim 3 wherein said sleeve has an inwardlyconverging end face at its smaller end and said orifice-creating, liquiddispersing member has a conical end face formed and adapted to seat onsaid sleeve end face.

5. The structure of claim 3 wherein said sleeve and orifice-creating,liquid dispering member are formed or relatively thin material and saidbody includes a reverse cone counterbore flaring outwardly from saidthroat and dening with the opposed, substantially parallel surface ofsaid last-named member a conical orilice in communication with saidchamber.

I6. The structure of claim 3 characterized by and including a passageformed in said body and communicating said chamber with the area outsidesaid body.

7. The structure of claim 3 wherein said chamber is of relatively thinfrusto-conical configuration extending substantially the length of saidsleeve and bore and characterized by and including a passage formed insaid body and communicating a portion of said chamber adjacent thelarger end of said sleeve with the area outside said body.

8. The structure of claim 8 characterized by and including meanslimiting the movement of said orificecreating, liquid dispersing memberaway from said smaller sleeve end.

9. The structure of claim 3 characterized lby and including an air-uiddispersing and separating element, said element comprising a barriermember removably secured to said body and encompassing the liquid outletthereof to receive all of said liquid as it flows from the orificecreated by said orifice-creating, liquid-dispersing member, said barriermember having an upper and lower portion, said upper portion havingrelatively large openings therein for the passage of air therethrough,said lower portion having relatively smaller openings for the passage ofliquid and resistance to the passage of air therethrough.

10. The structure of claim 10 characterized by and including anoutwardly conical circumferential wall on said last-named memberpositioned to receive fluid from said defined oriiice and to reverse thedirection of said flow.

11. In a hydraulic system, a pump having an intake side, a hydraulicfluid reservoir, a conduit delivering liuid to said reservoir, afluid-how accelerating, subatmospheric pressure zone creating deviceconnected to the delivery end of said delivering conduit and positionedto discharge air and fluid into said reservoir, said device beingoperative in response to flow of iiuid therethrough, a conduitcommunicating said pump intake side with the subatmospheric zone of saiddevice, a barrier member between the outlet of said device and the areawithin said reservoir, said barrier having openings in its upper portionof a size facilitating the passage of air therethrough and openings inits lower portion of a size to permit the passage of fluid and resistthe passage of air therethrough.

References Cited UNITED STATES PATENTS 401,75 3 4/1889 Lombard et al103-275 1,922,920 8/ 1933 .Aherne 103-272 2,297,185 9/1942 Hollander etal. 103-113 2,525,256 10/1950 'Byram 103-271 3,446,157 5/ 1969 Schafer103-272 FOREIGN PATENTS 404,281 10/ 1924 Germany 103-113 503,310 4/1939Great Britain 103-113 674,815 7/ 1952 Great Britain 103-113 HENRY F.-RADUAZO, Primary Examiner US. Cl. XJR. 417--

